The present invention relates to a process for preparing a novel thermoplastic resin composition. More particularly, the invention is concerned with a process for preparing a thermoplastic resin composition superior in the balance of rigidity, impact resistance and moldability or in the balance of flexibility and moldability.
Thermoplastic resins are widely utilized in the industrial field as materials superior in moldability and the utilization field thereof has been expanded by blending them with elastomers for modification. It is known that the effects of such blends, e.g., improvement of impact resistance and enhancement of rubbery properties are accelerated by heat-treating the blends dynamically. As processes which utilize a dynamic heat treatment there are known a process (prior art process A) which employs a crosslinking agent acting on both thermoplastic resins and elastomers, and a process (prior art process B) which employs a crosslinking agent acting mainly on only elastomers. However, as to compositions prepared by such conventional processes, improvements have been desired in the following points.